Hydraulic oscillator



Oct. 21, 1947. L. B. CASE HYDRAULIC OSCILLATOR Filed Dec. 10, 1942 4 Sheets-Sheet 1 w INVENTOR. haw G5. 5M1- Z ATTORNEYS Oct. 21, 1947. B. CASE 2,429,390

HYDRAULIC OSCILLATOR Filed Dec. 10, 1942 4 Sheets-Sheet 2 INVENTOR. rwv 0441-- BY M an m ATTORNEYS Oct. 21, L. B. CASE HYDRAULIC OSCILLATOR Filed Dec. 10, 1942 4 Sheets-Sheet 3 T0 HYDEAULIC MOTOR Z4 ATTORNEYS Oct. 21, 1947. L. B. CASE 2,429,390

HYDRAULIC OSCILLATOR Filed Dec. 10, 1942 4 Sheets-Sheet 4 4L ATTORNEYS Patented Oct. 21, 1947 HYDRAULIC OSCILLATOR Lynn B. Case, Bound Brook, N. J assignor to John Waldron Corporation, New Brunswick, N. J a corporation of New Jersey Application December 10, 1942, Serial No. 468,580

(Cl. fill-54.5)

Claims.

The invention relates to a hydraulic oscillator system wherein a fluid medium under pressure is utilize to impart reciprocal motion to a part to be reciprocated.

An object of the invention is to provide efficient and durable hydraulic reciprocal actuating means dependable and economic in operation.

Another object of the invention is to provide hydraulic reciprocal actuating means adapted for ready application to various specific uses.

Another object of the invention is to provide hydraulic reciprocal actuating means adapted to vary the path of travel of the member to be reciprocated.

The invention consists in the novel features, arrangements and combination of parts embodied by way of example in the apparatus hereinafter described as illustrated in the preferred form of the invention, and the invention will be more particularly pointed out in the appended claims.

Further objects, features and advantages of the invention will more clearly appear from the detailed description given below taken in connection with the accompanying drawings which form a part of the specification.

Referring to the drawings:

Fig. 1 is a partially schematic perspective view of one embodiment of the invention wherein a plurality of members are to be separately reciprocated;

Fig. 2 is a partially schematic sectional view showing further details of one unit of the system illustrated in Fi 1;

Fig. 3 is a side elevation, partly in section showing structural details of the hydraulic power generator or impulse pump somewhat schematically illustrated in Figs. 1 and 2;

Fig. 4 is an end view of the structure shown in Fig. 3;

Fig. 5 is a cross-sectional view taken at 5-5 of Fig. 3 and showing further structural details of said mechanism;

Fig. 5a is a cross-sectional view showing a modification of certain details shown in Fig. 5;

Fig. 6 is a longitudinal sectional view taken along the axis of one of the hydraulic motor units illustrated in Fig. 1 and showing further structural details additional to those shown in Fig. 2;

Fig. 7 is a sectional view showing certain details of a by-pass provided in the structure of Fig. 6;

Fig. 8 is a cross-sectional view Fig. 6, and

Fig. 9 is a cross-sectional view taken at 9-9 of Fig. 6.

In its broader aspects the invention contemplates a hydraulic motor having a reciprocating piston and a hydraulic generator such as an impulse pump or pulsator with a two-way fluid conduit interconnection therebetween: the impulse taken at 8 8 of pump producing intermittent pressure impulses which exert through said intercommunicating conduit, a relatively great force at predetermined intervals serving to intermittently move the m0- tor piston in one direction against a continuous and relatively smaller force suitably provided for moving said motor piston in the opposite direction during alternate periods, whereby said motor piston is reciprocated in accordance with said unbalanced forces.

In the present preferred embodiment hydraulic pressure is advantageously utilized as the relatively continuous pressure: and such embodiment for example comprises a relatively continuous hydraulic pressure, such as a pressure head which may be provided (Fig. 2) by a water main A, and an impulse pump or pulsator, such for example as B, producing intermittent pressure impulses working against said pressure head, and a hydraulic motor, such for example as C8, interposed between said pressure head and pulsator and operable intermittently in one direction by said impulses and alternately in the other direction by said pressure head, whereby said motor is actuated by the oscillation of the fluid medium.

The invention further contemplates means whereby the pressure impulses are cyclically varied to thereby vary the path of travel of the member to be reciprocated, such for example as D.

The invention further contemplates by-passing fluid around the hydraulic motor C from the pressure head A to the impulse pump B while preventing a return flow from the pump to the said head A through said by-pass; thus providing a means for assuring that the fluid is maintained to capacity in the impulse pump side of the system.

Since the invention has been found to be well adapted for use in reciprocating doctor blades in a printing machine, and since such use exemplifies the several salient features of applicant's invention, the embodiment of the invention as illustrated in Fig. 1 shows the use of the invention as applied to a printing machine by way of example. In this embodiment there are eight doctors to be reciprocated; and in order to prevent undue localized wearing of the printing cylinders, against which the respective doctors are held in wiping engagement under a certain degree of pressure, it is highly desirable that the path of reciprocation of the respective blades along their respective printing cylinder surfaces should be varied.

Referring more particularly to Figs. 1 and 2; a suitable source of relatively continuous hydraulic pressure is designated as A, and in the present embodiment this takes the form of a water supply pipe or main containing water under suitable pressure, which might be either a relatively fixed pressure head or otherwise. A source of intermittent hydraulic pressure is designated as B, which in th present embodiment is in the form of a hydraulic pump 01' pulsator adapted to produce intermittent pressure impulses. A hydraulic motor (which in Fig. 2 is designated C8) is interposed between the continuous pressure source A and the intermittent pressure source B in such manner that the opposed pressure sources cause an oscillation of the fluid medium between A and B which produces actuation of the hydraulic motor to effect reciprocation of the doctor D. In the particular multi-unit system illustrated in Fig. 1 there are eight elements D to be reciprocated (DI, D2 only of which are shown), a common source of continuous pressure such as A is interconnected to the respective hydraulic motors Cl-C8 inclusive and said respective motors are in turn interconnected with individual pump cylinders designated l-B inclusive of the pump mechanism designated generally as B.

With the foregoing general outline in view, the following detailed description of the several parts and their inter-relation will be better understood.

Pump

Referring more particularly to Figs. 3, 4 and 5; the pump comprises an upper frame portion 9, providing the cylinders l-4 inclusive above referred to, and a lower frame portion l0, providing the cylinders 58 above referred to. The frame parts 9 and H) are suitably bolted together with their plane of contact passing through the geometric axes of eccentric bushings II and 12 which are rotatably journalled in bearings provided jointly by the frame portions 9 and If) for rotation about their said axes. The bushings II and I2 serve as hubs for respective gears l5-l6 carried on their inboard ends, and the bushing II also carries a ratchet wheel M on its outboard end; and the bushings are suitably held against axial movement. The gears I5I6 are in mesh with respectively cooperating gears ll-l8 fastened to a countershaft 2| suitably journalled in bearings to rotate about an axis substantially parallel to the axis of said bushings. The bushings carry eccentrically disposed bearings 20-49 in which the drive shaft 23 is journalled for rotative movement. An eccentric 22 is fixed to the drive shaft 23 adjacent the bushing II by means of a pin such as 24. The shaft 23 carries fixed thereto asprocket Wheel 25 in driven engagement with a sprocket chain 29 which serves to deliver power from a suitable source (such as an electric motor not shown). The eccentric 22 is positioned within an eccentric yoke 28 pivotally supported by a stud pin 30 anchored in the frame member 9 and the eccentric yoke 28 is provided with a ratchet pawl 3| (Fig. 4) pivoted at 32 and resiliently held against its ratchet wheel l4 by a spring 33. It will therefore be seen that as the shaft 23 is rotated the eccentric 22 causes its yoke 28 to oscillate one oscillation per revolution to thereby move the ratchet wheel l4 through an angular movement of one tooth; which in the present embodiment, wherein fifteen teeth are provided, is equivalent to about 25 of angular rotation. Movement of the ratchet wheel [4 is transmitted to the bushing H and, through gears l6l8, shaft 2| and gears |5l1, to the bushing l2. Accordingly the eccentric bushings l |-l2 are intermittently rotated about their geometric axes 25 for each rotation of the shaft 23 and accordingly as the shaft rotates it revolves about the axis of the eccentric 22 and the drive shaft 23 is thereby progressively raised and lowered an amount equal to twice the eccentricity of the bushings II--l2 during each cycle of fifteen revolutions of the shaft 23. The chain drive 26 provides sufficient play to accommodate the eccentric displacement of the shaft 23 resulting from the revolution of the eccentric bushings l l-l 2.

The shaft. 23 carries secured thereto four eccentrics 34, 35, 36 and 31 (see also Figs. 1, 2 and 5) each carrying a ball bearing such as 38 and whose inner race is secured to its respective eccentric by a plate such as 39. The outer race of respective of said eccentrics is in driving engagement with a pai of oppositely disposed pistons positioned respectively within the cylinders previously designated I-5; 2-6; 3-4; and 4-8 (Fig. 1).

Each of the said pistons comprises a body member such as 40 to the upper end of which is secured a piston cup 4| by suitable securing means such as a washer 42 and a machine screw 43 secured in the piston 49. The said piston assembly is operatively disposed within a cylinder liner 44 which is rigidly fastened as by having a press fit within a bore provided in the frame structure. Each of the said cylinders (Fig. 5) is provided with a port 45 through which it is adapted to be placed in fluid communication with its respective hydraulic motor by means of a pip such as 46. Each cylinder is also provided with a port such as 41 which is in communication with a passageway provided by the bores 48 and 49. The passageway communicates with the inlet port 50 of a relief valve comprising a ball check 5| normally held against its seat by means of a valve rod 52 loaded by a weight 53 secured to its upper end; so that should excessive pressure be produced within the cylinder (such as by an undue interference of the passage of fluid through the pipe 46) the fluid under such pressure may pass through the passage 41-50, thereby lifting the check valve 5! and allowing the fluid to pass out through a valve outlet opening 54. A suitable deflecting plate such as 55 serves to direct such fluid as may escape from the valve outlets 54 of the upper four cylinders downwardly into the catch basin 56 provided in the lower frame member 9, and into which the valve outlets such as 54 from the lower four cylinders directly communicate. Such fluid as leaks inwardly past the pistons 40 passes out through an opening 56a into the catch basin 56.

From the foregoing it will be understood that as the shaft 23 rotates about its axis it moves the pistons such as 40 outwardly on their respective power strokes; the return stroke of each piston being effected by fluid pressure exerted thereon by the relatively continuous hydraulic pressure in the manner previously pointed out. B means of the mechanism previously described the shaft is caused to revolve about the geometrical axis of the eccentric bushings in which it is supported, so that the path of reciprocation of each piston is progressively moved inwardly and outwardly with respect to its cylinder-i. e., when the eccentrics ll-l2 have caused the shaft 23 to move to one of its outermost positions (see Figs. 1 and 5) the piston (as in cylinder 8) then engaged by the driving eccentric (as 31) which is in its outermost position will have attained a path of reciprocation nearest its cylinder head; and the successive reciprocations of this piston will progressively take place further and further away from its cylinder head until the shaft 23 has been returned to its opposite position of eccentricity, where the 'piston will have attained its position most distant from its cylinder head (corresponding to that shown in cylinder 4). Each piston will follow through this cyclical movement of stroke variation; and these cyclical changes in stroke variation will be correspondingly transmitted to the members, such as the doctors DI, DI, etc., to be reciprocated in the manner to be more particularly pointed out hereinafter.

The modification shown in Fig. 5a has been found entirely satisiactory and is desirable in some instances, such as where loads on the ball bearings 88 are relatively high or where it is otherwise desirable to eliminate the ball bearings. In such structure, the eccentrics 88 directly engage the inner ends of the pistons 48 and are preferably made of plastic-impregnated fabric integrally secured to a metal bushing 8i, which is keyed to the shaft 28. A nipple riser 82 is preferably inserted in the outlet We as a riser to raise the liquid level into engagement with the eccentric 88 for lubrication purposes.

Where it is only necessary to have four or less than four cylinders the upper frame member 8 and the cylinders and associated piston units are removed and replaced by a cover plate providing upper portions of the bearings for the eccentric bushings li-I2.

Hydraulic motor The hydraulic motor unit, previously referred to in connection with Figs. 1 and 2 and designated in its entirety as C, will now be more particularly described in connection with Figs. 6-9 inclusive. A first cylinder BI! and a second cylinder 8| are provided in the present embodiment by a cylinder body designated in its entirety as 82. The body 82 is provided with an integrally formed cylinder head 88 at one end and with a. removable cylinder head 84 at the other end, which removable head is screw-threaded into the interior bore of the cylinder 80 as at 85 so as to bring the flange 66 into engagement with the outer end of the cylinder. The head 84 is provided with an outwardly extending exteriorly threaded portion 61 for receiving a, nut 68 between which and the flange, 88 is rigidly clamped the upper end of a supporting bracket 88 which surrounds the portion 81 at its upper end and is adapted to be secured at its lower end to a suitable supporting structure (not shown).

A piston 10 is disposed within the cylinder 80 and a piston 1! is disposed within the cylinder 8|; these pistons in the present embodiment being integrally formed and constituting a compound piston cooperatingly disposed within the compound cylinder 82. The piston 10 is provided with a sealing cup 12 suitably secured thereto and the piston 1i is provided with a similar cup 18 suitably secured thereto. The rear end of said piston member is secured to the piston rod 14 which passes through the cylinder head 84 on the outer end of which is provided a packing gland designated in its entirety as 15. On its outer end the piston rod carries secured thereto a yoke 18 provided with a pin 11 which is shown passing through the end of a member to be connected to the piston member, such as one of the doctor members previously designated as D.

Between the cylinder head 68 and the piston 18 there is provided a pressure chamber 18 provided with an open port 18 in communication with a bore 88 (see also Fig. 9) formed in the cylinder member 82 and with the outer end of which a 75 influence of the eccentric pipe 8i is placed in liquid communication by being suitably secured to the cylinder member 82; the pipe 8! serving to place the pressure chamber 18 in communication with the water main A, in the manner previously described with reference to Figs. 1 and 2. Similarly, a pressure chamber 82 is provided between the cylinder head 88 and the piston 1i and is in communication by means of an open port 88 with the pipe 48 whose inner end is suitably secured to the cylinder member 82 and whose other end is adapted to be connected to one of the cylinders of the pump B in the manner previously described.

The pressure chamber 82 is provided with an outwardly extending bore 84 in communication with a transversely extending bore 85 (Fig. 8) forming the outlet side of a one-way valve which is provided withfa valve ball 88 seated over the mouth of the valve inlet 81 which is in communication at its lower end with the bore 88. This serves to place the pipe iii in fluid communication with the chamber 82 and therefore with the pipe 46 which is in open communication at its other end with the pressure chamber of one of the cylinders of the pump B; thereby providing a means of admitting fluid between the piston 1i and a piston 40 of the pump B to thereby maintain a substantially constant volume of fluid in the impulse side of the system. However the check valve 88 prevents fluid from passing reversely from the pressure chamber 82 into the passageway 88 during pressure impulses from the pump B. The piston 10 is reduced in diameter adjacent its juncture with the piston 1| so as to provide a peripheral space 88 which is in communication with the drain pipe 89; thereby providing for drainage of such fluid as may leak past the piston cup 12, and which otherwise would interfere with the operation of the mechanism.

From the foregoing it will be understood that as fluid enters the pipe 8| from the continuous pressure source A the piston 18 is caused to move on its power stroke, carrying with it the piston 1| on its return stroke, which in turn forces fluid out through the pipe 46 and thence into one of the cylinders of the pump B, which causes the piston 40 in the said cylinder of pump B to move on its return stroke. Conversely, as fluid is forced in the reverse direction through the pipe 86 under an impulse from the power stroke of a piston 40 in one of said pump cylinders, the piston H is actuated on its power stroke, carrying with it the piston 18 which is given its return stroke, and fluid from the pressure chamber 18 is forced outwardly through the port 19 and pipe 8! against the pressure source such as A. The foregoing operation causes a reciprocation of the piston rod 14 which is transmitted to the member to be reciprocated, such as D.

While in the presently preferred embodiment the motor takes the form of a compound cylinder having a double acting compound piston, it will be understood by those skilled in this art, from the foregoing, that the motor may take any suitable form comprehendingthe requisite features.

Operation The operation of the mechanism as a whole may now be followed by reverting to Fig. 2 in which the parts of one unit are indicated in the position corresponding to the unit of Fig. 1 including the pump cylinder 8 and motor unit C8. In this position of the parts the piston 40 is approaching the end of its power stroke under the 81, thereby forcing fluid from the cylinder 8 through the pipe 46 and into the cylinder member 62 where sufllcient pressure is exerted on the piston H to move the same on its power stroke and to return the interconnected piston on itsreturn stroke, to thereby displace the fluid from the pressure chamber 18 outwardly through the pipe BI against the continuous pressure supplied through the water main A. When the piston 40 has completed its power stroke the fluid pressure exerted in the pressure chamber 18 against the piston 10 moves the latter on its power stroke and returns the piston 'H toward.

its cylinder head thereby forcing the fluid out from the chamber 82 through the pipe 46 into the cylinder 8, causing the piston 40 to move on its return stroke, which is permitted due to the continued rotation of cam 31 until the low side of the cam is disposed adjacent the inner end of the piston, at which time the return stroke of the piston ends. Upon further rotation of the cam the piston is started on its outward or power stroke and the oscillation cycle of the unit is completed, during which oscillation cycle the piston rod 14 serves to transmit the respective power strokes of pistons 10 and H to the member D which is thereby reciprocated.

During the complete oscillation cycle of this unit the piston 40 is reciprocated in the path of movement nearest its cylinder (8) head due to the fact that the shaft 23 (Fig. 1) is at the point in its revolution nearest said cylinder head. Upon each successive rotation of the shaft 23 the corresponding successive reciprocations of the piston 40 of the cylinder 8 will take place further and further away from said cylinder head until the shaft 23 has been revolved about the geometrical axis of the eccentric bushings I|l2 which revolution, as above pointed out, will take place during each fifteen rotations of the shaft. By this means the member D which is reciprocated is caused to hunt back and forth during its reciprocation and this materially decreases the wear which would otherwise be localized on the surface of the printing cylinder with which the doctor is in wiping engagement.

Each of the remaining units of the pump goes through a cycle of operation similar to that previously described with reference to cylinder 8 and similarly cooperate with the respective motors CI, G2, etc., to cause a corresponding reciprocation of the members Di, D2, etc. It is particularly pointed out that the present invention provides a system wherein a single line hydraulic system is provided, thus reducing to a minimum the number of lines necessary per unit; likewise by utilizing a common source of pressure such as that supplied through the water main A the hydraulic I oscillating system is assured of being kept filled to capacity at all times despite the usual leakage and loss of fluid which is customary in such systems; furthermore by utilizing the pressure head as a means of effecting the return stroke of the impulse pump pistons the pump mechanism is materially simplified and smoothness of operation is enhanced. Similarly, the invention makes it possible to utilize a hydraulic motor free from the usual valve mechanism, thereby simplifying the motor both as to construction and operation. Further advantages will readily appear to those skilled in the art after understanding the invention.

Having thus described my invention with particularity with reference to the preferred apparatus for carrying out the same, it will be obvious to those skilled in the art, after understanding my invention, that other changes and modifications may be made therein without departing from the spirit and scope or my invention, and I aim in the appended claims to cover such changes and modifications as are within the scope of the invention.

What I claim is:

1. In a hydraulic oscillator system, the combination of a hydraulic motor having a doubleacting piston provided with means for connecting thereto a member to be reciprocated, a cylinder within which said piston is positioned and providing in cooperation with said piston oppositely disposed hydraulic pressure chambers, one of said chambers having a continuously open port providing means of liquid communication with a relatively continuous hydraulic pressure, a hydraulic pressure generator constructed and arranged to produce hydraulic pressure impulses, fluid conduit means between said generator and the other of said chambers, said motor and generator being so constructed and arranged that there is a differential of pressure exerted on said piston by said pressure impulses sufilcient to overcome intermittently said continuous hydraulic pressure exerted on said piston, whereby said piston is moved in one direction in timed relation to said hydraulic pressure impulses and is moved in the other direction by said constant pressure at periods intervening the periods of the pressure impulses to thereby cause said piston to reciprocate, and means operable in timed relation to said pressure generator for progressively varying the cyclical relationship of successive hydraulic impulses produced to thereby progressively vary the path of travel of said member to be reciprocated.

2. In a hydraulic oscillator system, the combination of a liquid conduit adapted to be connected at one end with a relatively continuous hydraulic pressure head, a liquid pulsator in communication with the other end of said conduit, 2. cylinder chamber provided in said conduit, a double-acting piston disposed for reciprocal movement within said chamber responsive to fluid movement in said conduit and adapted to be connected to an element to be reciprocated by said piston, said pulsator and the efiective areas of the opposite ends of said piston subjected respectively to said pulsating pressure and said relatively constant pressure being so constructed and arranged with respect to the intensity of pressure of said relatively constant pressure head that said piston is moved intermittently in one direction in timed relation with the hydraulic impulses produced by said pulsator and is moved intermittently in the opposite direction by said relatively constant pressure head in alternate timed intervals, and liquid communication means providing unifiow from the relatively constant pressure head side of said piston to the other side of said piston, whereby fluid may be admitted between said piston and pulsator at intervals between pulsations to maintain a substantially constant volume of fluid between said pulsator and piston.

3. In a hydraulic oscillator the combination of a hydraulic motor having two cylinders with respective pistons disposed one in each cylinder and said pistons being interconnected for actuation of each on its return stroke by the respectively alternate power stroke of the other, a first one of said cylinders being provided with means of communication with a continuous hydraulic pressure source for fluid pressure actuation of said first piston on its power stroke, a hydraulic pressure 9 generator comprising a cylinder, means of liqui communication between said generator cylinder and the second of said motor cylinders, a piston positioned in said generator cylinder, means for intermittently successively moving said generator piston in one direction to deliver a plurality of hydraulic impulses to said second motor piston to impart thereto at each impulse a power stroke and thereby a return stroke to the first of said motor pistons, said generator piston being movable on each of its return strokes by the fluid displaced upon the respective return strokes of spective of the said power strokes of the first of said motor pistons, and means operable in timed relation to said pressure generator for progressively varying the cyclical relationship of successive hydraulic impulses produced to thereby progressively vary the path of travel of said member to be reciprocated.

4. In a hydraulic oscillator the combination of a hydraulic motor having two cylinders with respective pistons disposed one in each cylinder and said pistons being interconnected for actuation of each on its return stroke by the respectively alternate power stroke of the other, a first one of said cylinders being provided with means of communication with a continuous hydraulic pressure source for fluid pressure actuation of said first piston on its power stroke, a hydraulic pressure generator comprising a cylinder, means of liquid communication between said generator cylinder and the second of said motor cylinders, a piston positioned in said generator cylinder, means for intermittingly successively moving said piston in one direction to deliver a; plurality of hydraulic impulses to said second motor piston to impart thereto at each impulse a power stroke and thereby a return stroke to the first of said motor pistons, said generator piston being movable on each of its return strokes by the fluid the second of said motor pistons effected by redisplaced upon the respective return strokes of the second of said motor pistons effected by respective of the said power strokes of the first of said motor pistons, and a one-way fluid communication means interconnecting the fluid from said continuous pressure source to the fluid intermediate said generator piston and the second of said motor pistons, said last means being constructed and arranged as to admit replenishing fluid to said intermittent pressure line between the said pressure impulse periods.

5. In a hydraulic oscillator the combination of a hydraulic motor having two cylinders with respective pistons disposed one in each cylinder and interconnected for actuation of each on its return stroke by the respectively alternate power stroke of the other, a first one of said cylinders being provided with means of communication with a continuous hydraulic pressure source for fluid pressure actuation of said first piston on its power stroke, a hydraulic pressure generator comprising a cylinder, means of liquid communication between said generator cylinder and the second of-said motor cylinders, a piston positioned in said generator cylinder, means for repeatedly moving said generator piston in one direction to deliver a plurality of hydraulic impulses to said second motor piston to impart thereto at each impulse a power stroke, said generator piston being movable on each of its return strokes by the fluid displaced upon the respective return strokes of the second of said motor pistons effected by the said power stroke of the first of said motor l0 pistons and means for cyclically varying the path of reciprocation of said generator piston.

6. In combination with means for exerting continuous liquid pressure, a hydraulic pump comprising a, cylinder, 9. piston operatively disposed within said cylinder and providing therewith a liquid chamber, said chamber being in continuous liquid communication with said first means, a cam for moving said piston toward the head of said cylinder, a drive shaft to which said cam is fastened, means for rotating said shaft about its axis to cause said cam to actuate said piston in one direction against said continuous liquid pressure, said piston being movable on its return stroke by said continuous liquid pressure, and means for revolving said shaft about an axis parallel to and spaced from the axis of rotation of said shaft to thereby vary the path of movement of said piston relative to said cylinder.

'7. In a hydraulic oscillator system provided with hydraulic motor means, a hydraulic pump comprising a cylinder having an outlet connected to said motor means, a piston operatively disposed within said cylinder, a cam for actuating said piston, a drive shaft to which said cam is fastened, means for rotating said shaft about its axis to cause said cam to actuate said piston, and means for varying the position of the axis of said shaft with respect to said cylinder to thereby vary the path of movement of said piston relative to said cylinder.

8. In a hydraulic oscillator system provided with hydraulic motor means, a hydraulic pump comprising a cylinder having an outlet connected to said motor means, a piston operatively disposed within said cylinder, a cam for actuating said piston, a drive shaft to which said cam is fastened, means for rotating said shaft about its axis to cause said cam to actuate said piston, and means for revolving said shaft about an axis parallel to and spaced from the axis of rotation of said shaft to thereby vary the path of movement of said piston relative to said cylinder.

9. In a hydraulic oscillator system provided with hydraulic motor means, a hydraulic pump comprising a cylinder having an outlet connected to said motor means, a piston operatively disposed within said cylinder, a driving eccentric for actuating said piston, a drive shaft to which said eccentric is fastened, means for rotating said shaft about its axis to cause said eccentric to actuate said piston, a pair of eccentric bushings disposed on respectively opposite sides of said eccentric and journalled for rotation about a common geometric axis and each provided with an eccentrically disposed journal, said shaft being rotatably mounted in said last mentioned journals, and means for rotating said eccentric bushings to thereby cause said shaft to revolve about the axis of said bushings, whereby said driving eccentric is orientated and the path of travel of said piston is varied.

10. In a hydraulic oscillator system provided with hydraulic motor means, a hydraulic pump comprising a cylinder having an outlet connected to said motor means, a piston operatively disposed within said cylinder, a driving eccentric for actuating said piston, a drive shaft to which said eccentric is fastened, means for rotating said shaft about its axis to cause said eccentric to actuate said piston, a pair of eccentric bushings disposed on respectively opposite sides of said eccentric and journalled for rotation about a common geometric axis and each provided with an ec entrically disposed journal, said shaft being rotatably mounted in said last mentioned, journals, eccentric means secured to said shaft, mechanism in driven engagement with said eccentric means and with said eccentric bushings for rotation of said bushings, whereby the rotation of said shaft causes rotation of said eccentric bushings and thereby revolves said shaft about the axis of said bushings.

11. In a hydraulic oscillator system provided with hydraulic motor means, a hydraulic pump comprising a pair of oppositely disposed axially aligned cylinders each having an outlet connected to said motor means, a pair of pistons operatively disposed within respective of said cylinders, a cam for actuating said pistons, a drive shaft to which said cam is fastened, means for rotating said shaft about its axis to cause said cam to actuate said pistons, and means for revolving said shaft about an axis parallel to and spaced from the axis of rotation of said shaft to thereby vary the path of movement of said pistons relative respectively to said cylinders.

12. In a hydraulic oscillator system provided with hydraulic motor means, a hydraulic pump comprising a pair of oppositely disposed axially aligned cylinders each having an outlet connected to said motor means, a pair of pistons operatively disposed within respective of said cylinders, a cam for actuating said pistons, a drive shaft to which said cam is fastened, means for rotating said shaft about its axis to cause said cam to actuate said pistons in one direction of their stroke, said pistons being movable in the other direction of their stroke, by said hydraulic motor means, and means for revolving said shaft about an axis parallel to and spaced from the axis of rotation of said shaft to thereby vary the path of movement of said pistons relative respectively to said cylinders.

13. In a hydraulic oscillator system provided with hydraulic motor means, a, hydraulic pump comprising'a cylinder having an outlet connected to said motor means, a piston operatively disposed within said cylinder, a driving eccentric for actuating said piston, a drive shaft to which said eccentric is fastened, means for rotating said shaft about its axis to cause said eccentric to actuate said piston, a pair of eccentric bushings disposed on respectively opposite sides of said eccentric and journalled for rotation about a common geometric axis and each provided with an eccentrically disposed journal, said shaft be ing rotatably mounted in said last mentioned journals, an eccentric secured to said shaft for rotation therewith and disposed adjacent one of said bushings, a pivotally mounted eccentric yoke in driven engagement with said last mentioned eccentric for oscillation thereby and provided with a ratchet pawl, a cooperating ratchet wheel secured to said first bushing for rotation thereof and in driven engagement with said pawl, a gear secured to said first bushing, a gear secured to the other of said bushings, a counter shaft geared at one end to said first bushing for rotation thereby and at its other end to the other of said bushings for rotation thereof, whereby the rotation of said drive shaft causes the rotation of said eccentric bushings and thereby revolves said shaft about the axis of said bushings.

14. In a hydraulic oscillator system the combination of, a hydraulic motor comprising a cylinder and a piston, a hydraulic generator comprising a cylinder and a piston, conduit means interconnecting said cylinders for liquid flow in both 12 directions, continuous pressure means for moving said motor piston in one direction to thereby force liquid from said motor cylinder and deliver hydraulic pressure through said conduit to said generator cylinder, said generator being provided with piston-actuating mechanism constructed and arranged to release said generator piston for movement in one direction under said hydraulic pressure delivered from said motor piston and to intermittently move'said generator piston in the opposite direction, the effective areas of said pistons being so proportioned as to create a relatively greater hydraulic pressure on the power strokes of said generator piston, whereby said motor piston is caused to reciprocate in response to said unbalanced hydraulic pressures between said cylinders, and means operable in timed relation to said pressure generator for progressively varying the cyclical relationship of successive hydraulic impulses produced to thereby progressively vary the path of travel of said member to be reciprocated.

15. In a hydraulic oscillator system the combination of, a hydraulic motor comprising a cylinder and a piston, a hydraulic generator comprising a cylinder and a piston, conduit means interconnecting said cylinders for liquid flow in both directions, continuous pressure means for moving said motor piston in one direction to thereby force liquid from said motor cylinder and deliver hydraulic pressure through said conduit to said generator cylinder, said generator being provided with piston-actuating mechanism and constructed and arranged to release at timed intervals said generator piston for movement in one direction under said hydraulic pressure delivered from said motor piston and to intermittently move said generator piston in the opposite direction at alternate timed intervals to create a relatively greater hydraulic pressure, whereby said motor piston is caused to reciprocate in response to said unbalanced hydraulic pressures between said cylinders, and means for cyclically varying the timing of said piston-actuating mechanism to thereby vary the path of travel of said generator piston and accordingly said motor piston. 1

' LYNN B. CASE.

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